1. Field of the Invention
The invention relates to a radio frequency device, and more particularly, to a radio frequency device capable of utilizing an impedance unit as a transmission line terminal for reducing crosstalk interference.
2. Description of the Prior Art
With the rapid progression of technology, the development trend of electronic products is toward thin profile, light weight, and small size. Furthermore, an electromagnetic interference (EMI) problem has become a very challenging design task with high operating frequency. How to suppress or cancel the EMI effect and ensure that electronic products can be operated in an appropriate electromagnetic environment is an essential issue. For example, the prior art utilizes an absorber in a radio frequency circuit to overcome crosstalk or suppress radiation power for preventing interference from other circuits.
Please refer to FIG. 1, which is a schematic diagram of a radio frequency device 10 with absorbers according to the prior art. The radio frequency device 10 includes an isolation substrate 102, a ground layer 104, a radio frequency circuit 106, an open stub ST, and an absorber 108. The open stub ST belongs to part of the radio frequency circuit 106. In the prior art, the absorber 108 can be pasted onto the open stub ST for suppressing the EMI effect. Generally, the absorber 108 is manually pasted onto the corresponding open stub ST during the manufacturing process of the radio frequency device 10. However, manually pasting the absorber 108 is time consuming, laborious, and inefficient. Further, the present circuit device may have tiny size, increasing probability of inaccurately pasting the absorber 108 onto the corresponding position due to human error, causing poor suppression effect for suppressing crosstalk or radiation power. In addition, the absorber is expensive, so employing several absorbers in the radio frequency device 10 results in higher cost of production of the radio frequency device 10. In short, using the absorber in the radio frequency device 10 for suppressing the undesired crosstalk and radiation power is time consuming, laborious and expensive.